Perhaps you should try some spelling variations:
hoc sach » hoc sinh, hoc cac, hoc anh
dua tren » dung tren
van hanh » van thanh, ban hanh, van anh
vuc van » duc van, luc van, thuc van
cam vuc » cam xuc
qua cam » qua cham, qua cac, qua ca
le lang » le tang, le dang, le xang
ly lang » ly hang, ly vang, ly lanh
cuu tre » cua tre, cau tren, cau treo

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: hoc sach ((ly lang) OR (le lang)) xa hoi. hieu qua cam vuc van hanh vi ((dua tren) or (cuu tre))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc sach ((ly lang) OR (le lang)) xa hoi. hieu qua cam vuc van hanh vi ((dua tren) OR (cuu tre))*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc sach ((ly lang) OR (le lang)) xa hoi. hieu qua cam vuc van hanh vi ((dua tren) or (cuu tre))*".